The present application relates to a data processing method, an information recording medium manufacturing management system, a recording data generation apparatus and method, and a computer program. More particularly, the present invention relates to a data processing method capable of efficiently generating recording data for an information recording medium, an information recording medium manufacturing management system for use therewith, a recording data generation apparatus and method for use therewith, and a computer program for use therewith.
Various software data, such as audio data such as music, image data such as movies, game programs, and various kinds of application programs (hereinafter, these will be referred to as “content”), can be stored as digital data on a recording medium, for example, a Blu-ray disc in which a blue laser is used, a DVD (Digital Versatile Disc), an MD (Mini Disc), and a CD (Compact Disc). In particular, a Blu-ray disc using a blue laser is a disc capable of high-density recording and is capable of recording a large amount of video content or the like as high-quality data.
Digital content is stored in these various information recording media and is provided to a user. The user reproduces and uses content in an owned reproduction device, such as a PC (Personal Computer) or a disc player.
In general, sales rights or the like of most content, such as music data and image data, are held by the creator thereof or the seller thereof. Therefore, when distributing these pieces of content, it is common practice that a fixed use limitation is imposed, that is, use of content is permitted for an authorized user so that copying without permission or the like will not be performed.
According to a digital recording apparatus and a recording medium, images and audio can be repeatedly recorded and reproduced without degrading them. Therefore, problems such as those described below have occurred: the distribution of illegally copied content via the Internet, the distribution of so-called pirated discs produced using CD-Rs and the like, onto which content has been recorded, and wide use of copied content stored in a hard disk of a PC or the like.
It is possible for a DVD or a large-capacity recording medium, such as a recording medium using a blue laser whose development has progressed in recent years, to record a large amount of data for one to several movies as digital information on one medium. When it has become able to record video information and the like as digital information in the manner described above, it has become increasingly important to prevent illegal copying and protect a copyright holder. In recent years, in order to prevent such illegal copying of digital data, various technologies for preventing illegal copying to digital recording apparatuses and recording media have been implemented.
For example, in a DVD player, a content scramble system is adopted. In the content scramble system, video data, audio data, and the like are encrypted and recorded on a DVD-ROM (Read Only Memory). A key used to decrypt encrypted data is given to a licensed DVD player. The license is given to a DVD player that is designed to comply with predetermined operation definitions such that illegal copying is not performed. Therefore, in the licensed DVD player, by decrypting the encrypted data recorded on a DVD-ROM by using a given key, images and audio can be reproduced from the DVD-ROM.
On the other hand, since a non-licensed DVD player does not have a key for decrypting encrypted data, it is not possible to decrypt encrypted data recorded on a DVD-ROM. As described above, in the content scramble system, a DVD player that does not satisfy conditions required at license time cannot play a DVD-ROM having digital data recorded thereon, so that illegal copying is prevented.
As one technique for eliminating unauthorized use of content, control configuration has been proposed in which presence or absence of tampering of content is verified by an information processing apparatus (reproduction apparatus) for reproducing content, content reproduction is permitted only when it is confirmed that the content has not been tampered with, and the content is not reproduced when it is confirmed that the content has been tampered with.
For example, in Patent Document 1, control configuration has been disclosed in which a hash value is calculated from a content file scheduled to be reproduced, the hash value is compared with a comparison hash value that is prepared in advance, that is, a comparison hash value calculated in advance on the basis of valid content data, when the newly computed hash value matches the comparison hash value, it is determined that there has been no tampering of content, and the process proceeds to a content reproduction process.
However, when a process for computing a hash value on the basis of content in the manner described above is to be performed, when the size of content data as the original data for which a hash value is computed is large, the processing load and processing time required for calculations become enormous. In recent years, as the quality of moving image data has become increasingly higher, the moving image data often has an amount of data of several GB to several tens of GB per content. The fact that a user device for reproducing content is made to perform such a content hash value computation process on the basis of large-size data causes problems to occur, for example, the data processing performance required for the user device becomes enormous, the time required to verify content becomes longer, and the content reproduction process cannot be performed efficiently.
when an information recording medium having content stored thereon is to be manufactured, a content editing entity for editing content, and an information recording medium manufacturing entity for creating a disc image as recording data for an information recording medium on the basis of edited content and for manufacturing a disc on which the recording data is recorded on the basis of a disc image are necessary. Furthermore, a management center for performing content use management and management of information recording medium manufacturing licenses and the like is necessary. Predetermined data is exchanged between these, and content-stored information recording media on which encrypted content, key information, and the like are stored are manufactured on the basis of a valid license.
However, in this manufacturing process, various kinds of data, for example, key data, a content certificate, and the like, which can be generated by only a specific entity, exist. It is necessary to generate these pieces of data efficiently and under strict management, to exchange them among the entities, and to record them.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2002-358011